The present invention relates to a heating or air-conditioning system for a motor vehicle that supplies separately air-conditioned air to each individual air-conditioned zone in the interior of the vehicle. In particular, the present invention relates to a heating or air-conditioning system having a heater, a cold air duct, and mixing spaces for mixing air to a specific temperature for each air-conditioned zone.
French Patent No. 2717747 discloses an air-conditioning system with various air-conditioned zones: xe2x80x9cfront rightxe2x80x9d (front passenger""s seat), xe2x80x9cfront leftxe2x80x9d (driver""s seat), xe2x80x9crear leftxe2x80x9d and xe2x80x9crear rightxe2x80x9d. The air temperature fed to each of the various air-conditioned zones can be set separately. In order to effect the separate controls, the air-conditioning system includes two air-conditioning units, one supplying the left-hand half of the vehicle and one supplying the right-hand half of the vehicle. The air-conditioning units can be used to supply the front area and the rear area with air which has been air-conditioned in different ways. This air-conditioning system is very costly since it requires two air-conditioning units, with each unit including a blower, an evaporator, a heater, and the corresponding air ducts. In addition, it can only be used in large-sized vehicles because of the large amount of space required. Therefore, the system has disadvantages in terms of expense and space required.
German Patent No. 39 40 361 discloses an air-conditioning system which can supply air to four air-conditioned zones. In this air-conditioning system, warm air and cold air are generated and fed to each air-conditioned zone via separate ducts. A mixing space is provided in the region of the air outlet openings for each respective air-conditioned zone. Warm air and cold air are mixed directly in the mixing space before emerging through the air outlet opening into the interior of the vehicle. Although the four air-conditioned zones can be supplied using an air-conditioning system having only one blower, one evaporator and one heater, this patent requires considerable installation space since two air ducts per mixing space supply air to each air-conditioned zone. In addition, this air-conditioning system generally does not adequately mix the warm and cold air because the warm air and cold air are not mixed until directly before emerging out of the air outlet nozzles. Therefore, it is frequently the case that insufficient mixing occurs so that hot and cold air masses emerge from an air outlet nozzles next to one another.
U.S. Pat. No. 5,016,704 discloses an air-conditioning system for motor vehicles including only two independently controlled air-conditioned zonesxe2x80x94the front area and the rear area. In the disclosed system, the air-conditioning system is bifurcated downstream of the evaporator. In each of the two parts, the quantity of air which is heated by the heater or fed past the heater is regulated by an air flap. The warm air and cold air can be mixed down-stream of the heater and, after mixing, are fed to the individual outlet nozzles. One disadvantage of this air-conditioning system is that it requires a large installation space. In addition, this system does not ensure sufficient mixing of the air. A further disadvantage of this system is that only two zones can be air-conditioned.
German Patent No. 44 22 120 discloses an air-conditioning system which has a left/right regulator. In order to obtain a compact design, the cold air is fed past the side of the heat exchanger and mixed with the warm air downstream of the heat exchanger. Despite the relatively compact design, the installation space required by this air-conditioning system is still comparatively large because of the space required by the warm air swivel flaps. These swivel flaps execute a swiveling movement into the mixing space and are located downstream of the heat exchanger. A further disadvantage of this system is that it does not ensure optimal mixing of the cold and warm air; since, even in its opened state, the warm-air swivel flap brings about a certain degree of separation of the cold and warm air masses. That is, because the air is fed past the heater laterally, the air which is diverted into the lateral channels is usually poorly mixed. For this reason, the system does not reliably ensure the desired air-conditioning of the diverted air. Moreover, this air-conditioning system is not suitable for supplying more than two air-conditioned zones.
An object of this invention is to provide an improved heating or air-conditioning system having a simple design, requiring a small installation space and including the ability to supply air which has been air-conditioned in different ways to a plurality of air-conditioned zones. Another object of the invention is to provide optimal mixing of cold and warm air in the heating or air-conditioning system, even despite the small installation space required, so that a set air temperature is provided in each air duct. In this way, the air emerging from air outlet openings in a respective air-conditioned zone is of uniform character, i.e., the emerging air has a constant temperature over the entire outlet cross section of the air outlet opening.
These objects are achieved according to the present invention by means of a heating or air-conditioning system including a heater positioned within a housing for warming air and guiding the warmed air into a mixing space. A cold air duct, including a sub-duct for guiding air into the mixing space, is disposed beneath the heater. A mixing flap is disposed upstream of the heater and the sub-duct. The position of the mixing flap controls the ratio of air entering the heater and the sub-duct so that air from the heater and air from the sub-duct mix to a pre-selected temperature in the mixing space. The mixing space is adapted to communicate with an air duct and an air outlet nozzle to guide air into an air-conditioned zone.
These objects are also achieved according to the present invention by means of a heating or air-conditioning system for a motor vehicle including a heater located in a housing. One cold duct, which comprises a plurality of separate pneumatically parallel sub-ducts, leads under the heater. A plurality of air mixing spaces, disposed adjacent the heater and extending essentially the full height of the heater, are separated by dividing walls and receive warm air from the heater and cool air from the plurality of sub-ducts. Air control elements comprising mixing flaps mix respective quantities of the warm air and cool air to a pre-selected temperature. Each movable mixing flap is disposed upstream of the heater such that in a first position the mixing flap closes off one of the plurality of sub-ducts and in a second position the mixing flap closes off a portion of the inlet of the heater. Each air mixing space communicates with at least one air duct and at least one air outlet nozzle to guide mixed air to a respective air-conditioned zone.
Further objects, features and advantages of the present invention will become apparent from the detailed description of preferred embodiments that follows, when considered together with the attached figures of drawing.